Hello I've just build the VC-LFO-2. Only problem is, I am not getting it to work. In the first place, the yellow led does nothing, checked the wires, all good. I'm only not sure about the DPDT switch. I really think I've connected it wrong, could it be that I've placed the switch upside down? Does it make any change?

Checked the alignment of the IC's, all good. 1 little question, tje 1uF cap, does it need to be a tantulum? No I've used a polyester film version. It didn't say it had to be a tantulum in the BOM. I will upload some pics asap!

did you calibrate it?
When I built it I thought it wasn't working, the led wouldn't light up, nothing. I had one error near 7555 and lm741, after fixing that, still the same... Ihad one of the multiturn trimpots way low, and the frequency was loooooow, started calibrating it and it worked.

That could be a logical explanation! I did not calibrate it yet. Tried to, but the scope wasn't showing me a sawtooth only once. This was on the 1x setting on the DPDT switch. So the question also is, does C1a really needs to be a tantalum? Yves doesn't say it in the B.O.M. but he does say it in the calibrating proces. Still a little bit confused over here :S

I am not really familiar with oscilloscopes so can you tell me what settings to use on the scope?

Is there an error in the PCB where the black wire is? Where did you get this board? It looks commercially fabricated, not hand etched._________________My synth build blog: http://gndsynth.blogspot.com/

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